Moveably-Coupled Screen Actuators

ABSTRACT

A speckle damping system for dampening speckle on a projection screen for a projection display system employing coherent or partially coherent light sources (e.g., lasers, LEDs) are disclosed. In one embodiment, a rotatably coupled system is disclosed, comprising: a set of actuators; a set of rotatably coupled mounts, each of said set of rotatably coupled mount capable of mounting at least one said actuator; and wherein said at least one actuator mounted on said rotatably coupled mount is in moveable mechanical communication with said projection screen. In another embodiment, a linearly coupled system is disclosed comprising: a set of actuators; a set of linearly coupled mounts, each of said set of linearly coupled mount capable of mounting at least one said actuator; and wherein said at least one actuator mounted on said linearly coupled mount is in moveable mechanical communication with said projection screen.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/109,791 filed on Jul. 5, 2016, which claims benefit to InternationalPatent Application No. PCT/US2015/010064 filed on Jan. 2, 2015, whichclaims the benefit of priority to U.S. Provisional Patent ApplicationNo. 61/923,256 filed on Jan. 3, 2014; U.S. Provisional PatentApplication No. 61/982,530 filed on Apr. 22, 2014; and U.S. ProvisionalPatent Application No. 62/096,343 filed on Dec. 23, 2014, all entiretiesof which are incorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to projector displays systems and, moreparticularly, to systems and methods of reducing and/or dampeningspeckle on a projection screen.

BACKGROUND OF THE INVENTION

In projector systems that use either coherent light or partiallycoherent light sources (e.g., lasers, LEDs or the like), an issue ofspeckle may occur. Speckle arises due to the interference of thecoherent or partially coherent light that reflects and/or scatters froma projector screen. Speckle is typically an undesirable visible artifactthat projector system designers seek to eliminate and/or abate.

It is known in the art that inducing vibrations on the projector screen(e.g., in particular, in the direction of the viewers, or z-axis (wherex-, y-axis substantially describe the plane of the screen) tend toreduce and/or eliminate such speckle.

Several solutions are noted in the art—for example:

-   -   (1) United States Patent Application 20120206784 to CHAN et al.,        published on Aug. 16, 2012 and entitled “DEVICE FOR REDUCING        SPECKLE EFFECT IN A DISPLAY SYSTEM”;    -   (2) United States Patent Application 20110194082 to Desai,        published on Aug. 11, 2011 and entitled “MICROELECTROMECHANICAL        SYSTEM WITH REDUCED SPECKLE CONTRAST”;    -   (3) United States Patent Application 20090034037 to Khan et al.,        published on Feb. 5, 2009 and entitled “METHOD AND SYSTEM FOR        REDUCING SPECKLE BY VIBRATING A LINE GENERATING ELEMENT”;    -   (4) United States Patent Application 20130010356 to Curtis et        al., published on Jan. 10, 2013 and entitled “SPECKLE REDUCTION        USING SCREEN VIBRATION TECHNIQUES AND APPARATUS”;    -   (5) United States Patent Application 20060238743 to Lizotte et        al., published on Oct. 26, 2006 and entitled “SPECKLE REDUCTION        OPTICAL MOUNT DEVICE”

all of which are hereby incorporated by reference in their entirety.

SUMMARY OF THE INVENTION

A speckle damping system for dampening speckle on a projection screenfor a projection display system employing coherent or partially coherentlight sources (e.g., lasers, LEDs) are disclosed. In one embodiment, arotatably coupled system is disclosed, comprising: a set of actuators; aset of rotatably coupled mounts, each of said set of rotatably coupledmount capable of mounting at least one said actuator; and wherein saidat least one actuator mounted on said rotatably coupled mount is inmoveable mechanical communication with said projection screen. Inanother embodiment, a linearly coupled system is disclosed comprising: aset of actuators; a set of linearly coupled mounts, each of said set oflinearly coupled mount capable of mounting at least one said actuator;and wherein said at least one actuator mounted on said linearly coupledmount is in moveable mechanical communication with said projectionscreen.

In another embodiment, both rotatably coupled systems and linearlycoupled systems may further comprise a magnetic coupling system,comprising: a first magnetic element, said first magnetic elementaffixed to said projector screen; a second magnetic element, said secondmagnetic element affixed to substantially proximal to said actuator; andsaid second magnetic element being substantially proximal to said firstmagnetic element such that the magnetic force between said first andsaid second magnetic elements capable of substantially maintaining adesired mechanical communication of said actuator with said projectionscreen.

Other features and advantages of the present system are presented belowin the Detailed Description when read in connection with the drawingspresented within this application.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced figures of thedrawings. It is intended that the embodiments and figures disclosedherein are to be considered illustrative rather than restrictive.

FIG. 1A is front view of a conventional projector screen with mechanicalactuators coupled to the screen on the back of the screen.

FIG. 1B is a side view of a conventional projector screen withmechanical actuators coupled to the screen in a substantially fixedmanner.

FIGS. 2A and 2B depict a mechanical actuator that is rotatably coupledto a support structure that tends to provide proper coupling between theactuator and the screen—that have a substantially flat engaging surfaceand a substantially curved engaging surface, respectively.

FIGS. 3A and 3B depict two alternative embodiments of a rotatablycoupled actuator system.

FIGS. 3C and 3D depict two additional alternative embodiments of arotatably coupled actuator system—as shown in FIGS. 3A and 3B andadditionally comprising a counterbalance weight.

FIG. 3E depicts one additional alternative embodiment of a rotatablycoupled actuator system comprising a dynamically varying weight asbiased against the screen.

FIGS. 4A and 4B depict two alternative embodiments of a linear coupledactuator system.

FIG. 5 depicts one embodiment of a magnetically coupled actuator system.

FIG. 6 depicts one embodiment of a servo-motor coupled actuator system.

FIGS. 7A through 7H are a set of various perspective drawings of onependulum embodiment.

FIGS. 8A through 8H are a set of various perspective drawings of anotherpendulum embodiment.

FIG. 9A shows an analysis of several embodiments of pendulum screenshakers described herein.

FIG. 9B depicts one such embodiment of a pendulum screen shakercomprising such a counterweight.

FIGS. 10A through 10B depict several different views of one particularembodiment of a pendulum screen shaker comprising a counterweight.

FIGS. 11A through 11C depict several other different views of oneparticular embodiment of a pendulum screen shaker comprising acounterweight.

FIGS. 12A and 12B depict one embodiment of a pendulum screen shakercomprising a counterweight at rest and with relative motion betweenpositions.

FIG. 13 depicts an embodiment of a dual-linkage pendulum screen shaker.

FIG. 14 depicts an embodiment of a diving board voicecoil mount on ascreen shaker.

DETAILED DESCRIPTION

Throughout the following description, specific details are set forth inorder to provide a more thorough understanding to persons skilled in theart. However, well known elements may not have been shown or describedin detail to avoid unnecessarily obscuring the disclosure. Accordingly,the description and drawings are to be regarded in an illustrative,rather than a restrictive, sense.

As utilized herein, terms “component,” “system,” “interface,”“controller” and the like are intended to refer to a computer-relatedentity, either hardware, software (e.g., in execution), and/or firmware.For example, any of these terms can be a process running on a processor,a processor, an object, an executable, a program, and/or a computer. Byway of illustration, both an application running on a server and theserver can be a component and/or controller. One or morecomponents/controllers can reside within a process and acomponent/controller can be localized on one computer and/or distributedbetween two or more computers.

The claimed subject matter is described with reference to the drawings,wherein like reference numerals are used to refer to like elementsthroughout. In the following description, for purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the subject innovation. It may be evident, however,that the claimed subject matter may be practiced without these specificdetails. In other instances, well-known structures and devices are shownin block diagram form in order to facilitate describing the subjectinnovation.

Introduction

The current state of the art for speckle reduction of laser-basedprojected images is to vibrate the projection screen very slightly inthe direction of the projected light, along the line of sight of aviewer. The most effective implementation of this technique is toinstall an array of mechanical shakers/actuators (e.g., “Voice Coils”,ultrasound transducers, solenoid, shaker and the like) mounted behindthe projection screen.

Such references employing such voice coils are disclosed in:

-   -   (1) United States Patent Application 20120019918 to Dunphy et        al., published on Jan. 26, 2012 and entitled “SYSTEM AND METHOD        FOR REDUCING VISIBLE SPECKLE IN A PROJECTION VISUAL DISPLAY        SYSTEM”; and    -   (2) United States Patent Application 20100312106 to Blalock et        al., published Dec. 9, 2010 and entitled “ULTRASOUND IMAGING        BEAM-FORMER APPARATUS AND METHOD”

and herein incorporated by reference in its entirety.

One possible drawback to using mechanical actuators/shakers (of any typeor kind—such as voice coils, ultrasound actuators or the like) is thatit may be desired to have accurate placement of the actuator veryclosely to the back of the screen, but not so closely that the actuatorpushes against the screen. In such a case, the outline of the actuatormay produce a “dimple” or an otherwise impression of itself, which maybe easily visible and distracting.

FIG. 1A shows a front view of a projector screen 102 with an array ofconventional mechanical actuators 104 in physical proximity with theprojector screen from behind the screen. FIG. 1B is a cross-sectionalview of the conventional array of actuators 104 in contact with screen102. Actuators 104 may be held in position by support 106—e.g.,typically in a fixed position. A projector system is depicted inschematic format in FIG. 1B. Projector system 100 may comprise a lightsource 108 (typically, coherent or partially coherent sources, likelasers or LEDs), a modulator 110 which may receive light from source 108and create a modulated light source to illuminate projector optics 112to form a final image on screen 102.

Although the laser and/or partially coherent projector system may be ofany type or construction known, in some embodiments, the laserprojection system may comprise, for example, a dual modulation DMDprojection system. The dual modulation system may comprise a reducedinitial amount of speckle operation of the screen shakers compared tocommercial single modulation (e.g., 3 chip DLP) laser projectors, andwhich the reduced initial amount of speckle is further reduced byoperation of the screen shakers.

The laser projection system may comprise a 3 chip DLP projection system.The laser projection system comprises a 3 chip DLP six-primary laserprojection system. The laser projection system comprises a 6 chip DLPsix primary projection system. The laser projection system producesimages on the screen having a contrast ratio in excess of 99,999:1.

The laser projection system produces images on the screen having adynamic contrast ratio between scenes in excess of 999,999:1. The laserprojection system produces images on the screen having a single framecontrast ratio of at least 100,000:1 and a dynamic intra frame contrastratio in excess of 1,000,000:1.

As noted, if the contact between the actuators 104 and screen 102 is notsubstantially precise, then an outline of the actuators 104 may becomevisible upon the screen and adversely affect the speckle reduction asdesired. In fact, if the screen 102 is induced to move at all (e.g., bychange in air pressure due to air conditioning or, possibly from a doorto the theater opening and/or closing, or from the expansion and/orcontraction of the screen with temperature), then the actuators 104 mayalso become visible or they may lose contact with the screen resultingin the speckle reduction being abated. It may be desirable that theforce of the actuator against the screen is maintained substantiallyconstantly over the range of movement of the screen.

In many embodiments, it may be desirable to induce vibrations (e.g.,from actuators) that are more than pure Z-axis vibration (i.e.,vibrations along the viewer's line of sight to the screen). Pure Z-axismay not be sufficient in many case to mitigate speckle. In many cases,the interference patterns may be quite deep (e.g. if the viewerperceives speckle and moves his/her head closer and farther from thescreen without moving side to side or up and down, the speckle patternmay tend to change very slowly). Similarly, moving the screen in the Zaxis may not change the interference pattern significantly. Thus,vibrating the screen in the Z axis (e.g., where the intention is for theeye to integrate over the variations in interference patterns) may notbe effective. Instead, speckle may be better reduced by creating waveson the screen.

So, in the case of using stationary actuators (e.g., as in FIGS. 1A and1B), if the actuators are too close to the screen, the viewers mayperceive two problems: (i) dimples (made by the contact of the actuatoron the screen) and (ii) speckle in the dimples only (because in theseareas there tend to be only Z-axis movement). For the case where theactuators are too far from the screen, they don't even touch the screen,there is no vibration and there is no speckle reduction at all.

One Embodiment

FIG. 2A depicts one embodiment of an actuator support structure 200.Structure 200 may be a rotatably coupled mount, where the mount iscapable of mounting or attaching an actuator 104 on a first supportportion 202. Any suitable means of mounting and/or attaching theactuator to the first support portion may be suitable—e.g., mechanicalclipping, affixing, gluing, soldering or the like. First support beam202 may be, in turn, rotatably attached to a second support portion206—e.g., possibly by a pivot 204. Second support portion 206 may befixedly or adjustably set, affixed and/or supported in place to anyother suitable structure and/or position in the theater (notshown)—e.g., in order to provide a substantially suitable stable framefor the first support portion. It will be appreciated that, althoughonly one actuator is shown on a support structure, it is possible toconstruct a set and/or an array of such support structure(s) thatsupport the entire set of actuators for a screen—either individually, asubset or the entire set of actuators. The present application is notlimited to merely one support structure for one actuator; but the scopeof the present application encompasses all such support structures.

In one embodiment, second support portion 206 may be (optionally)adjustably set—e.g., for example, as shown by dotted line 201. Thisadjustable setting may be preferentially set by theater personnel—e.g.,to adjust the pressure actuator 104 makes upon screen 102 and/or toadjust the position of the actuator in the middle range. In oneembodiment, an adjustment weight, as described herein, may be set toadjust the pressure suitably so that the actuator 104 makes desirablecontact with the screen (e.g. to abate and/or dampen speckle); but notso much as to make a visibly noticeable dimple in the screen to theviewers (and, possibly, abate and/or dampen speckle reduction).

Once a pivot point 204 is set, first support portion 202 may berotatable about the pivot—e.g., for example as shown by arc 203.Rotatable movement of the actuator 104 may be desirable in certainsituations. For example, if the screen has some motion (e.g., as mightbe induced by changes in air pressure, ground movements or the like),then the actuator may be allowed to move in response to the screen andcontinue to in contact with the screen and thus, provide continuedspeckle reduction. In addition, movable actuator may be able to dampenthe motion of the screen itself.

In FIG. 2A, it may be seen that actuator 104 may have a substantiallyflat surface for engaging with the screen. However, in FIG. 2B, actuator104 b may have some form of curved feature and/or surface in which toengage with the screen. Such a curved surface may be desirable if thedisplacements of the actuator with respect to the screen cause a sharpedge of the actuator to become visible to the viewer and/or have anundesirable effect on the dampening of the speckle. It may be understoodthat the curvature of the actuator may be circular or spherical (or aportion thereof), bent, bowed, arched and/or arcuate—in such a manner asto provide no (or at least less) detectable edges of the actuator whenthere is relative movement of the screen with the actuator.

Such a curved actuator may be desirable in operation, if the actuator isnot substantially parallel to the screen (e.g. due to misalignment ofthe mount or large screen displacements). In such a case, one edge ofthe flat actuator may press harder against the screen surface which inextreme cases may cause an arc-shaped imprint on the screen. Thus, acurved actuator (for example, one where the actuator surface may be asection of a larger sphere) would tend to present a consistent contactsurface over a range or rotations. The curvature radius may be between afew inches to ‘d’ the length of the pendulum. In addition, as notedabove, pure Z-axis vibration may not reduce speckle—and in particular ifspeckle is still apparent within the contact area of a flat actuator.The curved actuator would tend to reduce the area that moves simply inthe Z axis and improve the speckle reduction in the contact area.

In many embodiments, it may be desirable to suitably construct thelength of the first support/pendulum portion for several advantages,such as:

-   -   (1) If the pendulum length is long with respect to the range of        motion of the screen (e.g., that the actuator had to follow)        then the variation in angle is small and that reduces any        asymmetrical imprint of the skewed actuator on the screen. If        the actuator is small then, for any angle, the effect of the        asymmetrical imprint of the actuator is reduced. A larger ratio        of pendulum length to actuator size reduces the imprint but not        the angle. Angular variations may tend to cause an edge of the        actuator to become visible.    -   (2) For the pendulum support schemes, the moment of force varies        with large angles of the pendulum and hence the force applied        through the actuator to the screen varies with angle. If the        pendulum is long, then it may allow for significant Z-axis        movement without significant change of angle of the pendulum and        hence may tend to maintain an approximately constant force on        the screen.    -   (3) The pendulum schemes may have a natural frequency (e.g., if        the screen was to be removed and the actuator pushed, it would        tend to oscillate at its natural frequency). It may be desirable        that the natural frequency be designed to be different from the        frequency of the actuator vibration otherwise the pendulum may        vibrate instead of the screen. A long pendulum may tend to allow        for a low natural frequency.

Other Embodiments

FIGS. 3A and 3B depict alternative embodiments of an actuator supportstructure. As may be seen, an additional mass may be placedadvantageously on the support structure. In these embodiments, it may bepossible to adjust the force with the additional mass (e.g., as placedon either the first support portion or the second support portion) onthe screen as desired for the screen material. In both FIGS. 3A and 3B,the force may be adjusted by adjusting the mass shown.

For example, the mass may be adjusted as follows:

-   -   (1) In FIG. 3A—Let distance 310 (I₁) denote the distance from        the pivot to the attachment point of the mass, and distance 312        (I₂) denote the distance from the pivot to the center of mass of        the actuator and let P₁ be the length of the pendulum. The force        on the screen would be:

$F = {{m*g*( \frac{l\; 1}{P_{1}} )} - {m_{cg}*g*( \frac{l\; 2}{P_{1}} )}}$

-   -    where g is the acceleration due to gravity and m is the mass of        the attached mass and m_(cg) is the mass of the actuator at the        center of gravity of the actuator.    -   (2) In FIG. 3B—The force on the screen would be:

F=m*g

FIGS. 3C and 3D are additional embodiments of actuator supportstructures (substantially following the embodiments of FIGS. 3A and 3B)in which the support structure is extended past pivot points 204 a and acounterweight 320 is supplied to advantageously provide desirablebalance of the actuator support structure.

FIG. 3E is yet another embodiment of an actuator support structure inwhich a dynamically variable and/or varying mass and/or force 313 isapplied to dynamically vary the bias of the actuator against the screen.Variable mass and/or force 313 may be supplied by a variable springforce, variable weights, piezo structures and/or any other suitable massand/or force known. Such variable weight and/or force may in addition beapplied according to signals supplied by a controller 314. Suchcontroller may receive input signals from one or more possiblesensors—e.g., a photo sensor 316 a and/or a force sensor 316 b. Photosensor 316 a may be a camera and/or some image capture/detection devicethat is sensing/regarding the image on the screen and detecting theamount of (or any change in) the speckle displayed on the screen. If thephoto sensor sends signals that the controller may interpret that achange (e.g., either more or less) in bias of the actuator against thescreen may improve the speckle reduction, then the controller may sendsignals to the variable weight/force 313 to apply the desired change inbias.

In the case of the force detector 316 b, these detectors may be piezoforce sensors, embedded in or associated with the actuator (or any otherknown means of detecting contact force and/or bias that is in mechanicalcommunication with the screen) that send signals to the controller 314in order to change bias of the variable weight and/or force as desired.

In another embodiment, a method for correcting for artifacts and/oradjusting image projection includes the steps of illuminating a screenwith a test image, identifying at least one shaker induced artifact, andadjusting at least one shaker parameter to reduce at least one shakerinduced artifact. The at least one parameter comprises, for example, oneof a frequency of the shaker, a shape of the shaker, a motion induced bythe shaker, a pressure of the shaker (e.g., pressure against orplacement of the shaker adjacent to the screen), a pendulum balance ofthe shaker, a contact area of the shaker, a modulation of the shaker, anangle of the shaker, a mechanical adjustment of an assembly holding theshaker, an adjustment changing a proximate position of the shakerrelative to the screen. The at least one shaker induced artifact maycomprise, for example, a speckle pattern associated with a contact area(or “contact” area) of the shaker. The step of adjusting may comprise,for example, activating a remote control. The adjusting may comprisemanual placement of weights on a lever that, upon movement, brings ashaker back into equilibrium adjacent and in “contact” with the screen(contact without significant pressure).

The step of activating the remote control may comprise identifying atleast one of a plurality of shakers and sending a control signal to theidentified shaker(s). The step of adjusting may comprise, activating aremote control for a group or plurality of shakers adjacent to thescreen. The identified shakers comprise a set of shakers within aplurality of shakers, and the control signal is configured to adjusteach of the identified shakers in a similar way.

The step of adjusting may comprise, for example, adjusting a moment ofinertia of mechanical device configured to place the shaker at alocation directly adjacent to a non-viewing side of the screen. Themechanical device may comprise, for example, a weighted swing-arm. Thestep of adjusting may comprise moving the weight with respect to theswing-arm. The mechanical device may comprise a movable extensionattached to the weight and wherein the adjustment comprises increasingor decreasing an amount of leverage the weight applies through theextension to an arm of the mechanical device by extending or retractingthe movable extension. Extending or retracting the movable extension, orother types adjustment discussed elsewhere herein, may be electricallyactivated, and may be activated by remote control. Adjusting the momentof inertia may comprise adding weight to the swing arm or othercomponents as described elsewhere herein to which the shaker isattached.

The step of adjusting may comprise, for example, adjusting the shakersuch that a screen coupler attached to the shaker is directly adjacentand parallel to the screen. The adjusted shaker may be, in variousembodiments, for example, in contact with the screen but balanced suchthat it does not exert pressure on the screen. The adjusted shaker is,for example, as close as possible to the screen for maximum specklereduction with a minimum of test image artifacts induced by the shakerand coupler.

The adjusted shaker may be, for example, in contact with the screen andbalanced such that it exerts enough pressure on the screen to maintaincontact with the screen, but not enough pressure to inducepressure/contact related artifacts in images displayed on the screen.

The adjusted shaker coupler may be, for example, in contact with thescreen and balanced such that it exerts enough pressure on the screen toremain in contact and adjacent to the screen without causing aprotrusion of the screen.

The method may place the shaker such that the contact and adjacency ofthe shaker coupler remains (moves back to equilibrium) in light ofscreen movement due to any one or combination of air conditioning orventilating systems, air currents to entrance and/or exit door openings,or other movements normally associated with a viewing screen during use,including motion induced by theme park ride cars, explosions, heatinduced motion, fans, or motion of props when said screen is installedat a theme park ride.

The shaker comprises, for example, a base shaking device, a couplerattached to the base shaking device, and a placement device attached tothe base shaking device, the method further comprising the step ofmaintaining a face of the coupler parallel and adjacent to the screen.

In another embodiment, a reduced speckle laser projection system maycomprise, for example, a screen installed at a venue, a laser projectionsystem configured to project images onto the screen, and a plurality ofscreen shakers disposed on a non-viewing side of the screen. Each screenshaker may be, for example, movably held in position via a correspondingplacement device configured to place the screen shaker directly adjacentto the screen with an amount of pressure that does not substantiallychange when the screen moves. The amount of pressure is, for example,mostly negligible, which is, for example, an amount of pressure does notcause any viewable surface variation on a viewing side of the screen.The surface variations on a viewing side of the screen from one or moreof mechanical, acoustical, or vibrational forces of the shaker. Theshaker is configured to cause surface variations comprising motion in aplane of the screen caused by the shaker. The surface variations on aviewing side of the screen are, for example, caused by one or more ofmechanical, acoustical, or vibrational forces of the shaker and not by apressure of the shaker on the screen.

The placement device may comprise, for example, a dual arm dual-pivotswing (as discussed in various embodiments further herein) thatmaintains a coupler of the shaking device parallel to the screen. In oneembodiment, the placement device comprises a dual arm dual-pivot swingthat maintains a coupler of the shaking device parallel to the screenwhile moving due to screen movement. The placement device may comprise,for example, parallelism mechanism configured to maintain a coupler ofthe shaker parallel to the screen while moving due to screen movement.The placement device may comprise a coupler motion parallel placementmechanism configured to maintain a coupler of the shaker parallel whereit would otherwise not be parallel due to shaker induced movement.

The placement device may comprise, for example, a coupler motionparallel placement mechanism configured to maintain a coupler of theshaker parallel where it would otherwise not be parallel due to shakerinduced movement.

Another Embodiment

FIG. 4A is yet another embodiment of an actuator support structure 300.In this embodiment, instead of being rotatably coupled, the actuatorsmay be linearly coupled (or otherwise in desired mechanicalcommunication) to the screen by a set of linear bearings 404 that may bemounted in a housing movably resting on the bearings. In FIG. 4, theactuator may be attached to a housing 406—and some bias structure ormeans may be applied to maintain a desired mechanical communication ofthe actuator to the screen. One bias may comprises a pulley 410 and amass 402. In this embodiment, the force on the screen is proportional tothe mass. In this embodiment, it may be noted that the force issubstantially constant over the full range of motion of the linearbearing, as follows:

F=m*g

FIG. 4B is another linearly coupled actuator to the screen. In thisembodiment, instead of a weight and pulley, the actuator may be biasedto the screen by a spring 420 that has a suitable biasing force tomaintain appropriate contact with the screen. In one embodiment, it maybe possible to adjust the tension on the spring such that the propermechanical communication between the actuator and the screen issubstantially zero force and that any deviation from that zero providesa counter-balancing force to restore that zero. In another embodiment, aspring may be placed such that, for the necessary range of motion, itsforce may tend to be maintained within an acceptable upper and lowerbound. Such a spring may be not unlike a pendulum that only “swings” atthe bottom of its arc. As such, this spring would only operate in arange where the force (while not constant) is substantially unchanged.In one embodiment, the actuator may be affixed to the screen in anymanner known, including adhesive, glue, tape, Velcro, magnetic stripesor the like.

Magnetic Field Coupling and/or Modulation

In some embodiments, it may be desirable to employ systems, methodsand/or techniques in order to maintain the proper coupling and/or biasof the actuator to the screen. In one embodiment, it may be possible toemploy magnetic field coupling (e.g., whether static or varying) inorder to maintain the proper coupling.

FIG. 5 is one embodiment of such a magnetic coupling system as made inaccordance with the principles of the present application. Actuator 104may further comprise an actuator magnetic element 504. Actuator magneticelement 504 may be either a permanent magnet or a varyingelectromagnetic element. If magnetic element 504 is a varyingelectromagnet (e.g., a solenoid or the like), then there may be anoptional controller 506 in order to vary the magnetic field desirably.In addition, 506 may comprise optional sensors that may detect anynumber of parameter that may be useful in the governing of the couplingand/or bias of the actuator to the screen. Suitable sensors mightinclude (but are not limited to): position sensors, motion sensors,accelerometers or the like.

On the screen 102, there may be place a screen magnetic element502—which may be either permanent (e.g. magnetic bar, magnetic strip orthe like) or varying electromagnet (e.g., with any suitable controllerand/or sensors, not shown).

In one case, the system may be designed or built to detect the amount offorce, or relative positions, of the actuator to the screen. If thesystem employs some varying magnetic field, then the system may bedesigned with the sensors providing proper feedback on position, force,velocity, and/or acceleration in order to maintain desired coupling.

It will be appreciated that the dashed lines in FIG. 5 denote that themagnetic coupling schemes as mentioned above may be employed in eitherthe rotatably coupled systems and/or the linearly coupled systems.

Other Embodiments

FIG. 6 is yet another embodiment of an actuator coupled to screen systemthat further comprises at least one servo-motor (e.g. 604, if actuatoris rotatably coupled; 606, if actuator is linearly coupled). Inaddition, there may be at least one sensor 608 that may detect somecharacteristic (e.g., the position, speed and/or acceleration of theactuator in relation to the screen) of the mechanical communication ofthe actuator in relation to the screen. Signals from these optionalsensor(s) may be input into controller 610 that may, in turn, controlservo-motors (e.g., 604 or 606) to provide the desired bias to theactuators in relation to the screen.

Particular Pendulum Embodiments

FIGS. 7A through 7H are a set of various perspective drawings of onependulum embodiment (700). As may be seen, actuator 104 is mountedand/or affixed to first support member 702—which is rotatably mounted tosecond support member 706 via a pivot 704.

FIGS. 8A through 8H are a set of various perspective drawings of anotherpendulum embodiment (800). As may be seen, actuator 104 is mountedand/or affixed to first support member 802—which is rotatably mounted tosecond support member 806 via a pivot 804. An additional mass 810 ismounted on the first support member 802, as shown.

Embodiments with Counterweight

FIG. 9A shows an analysis of several embodiments of pendulum screenshakers given above. As may be seen, pendulum screen shaker 902 oflength ‘l’ is pivoted about point ‘P’ applying a force ‘F’ against thescreen at point ‘S’. m_(s) represents the mass of the voicecoil andwashers at bottom of pendulum. m_(w) represents a mass hung from an armof length ‘r’ attached to the screen shaker at the pivot, perpendicularto the pendulum.

This analysis looks for the variation in force ‘F’ vs the displacementof the bottom of the pendulum ‘d’. The moment (M_(mw)) due to m_(w) isgiven by:

M_(m_(w)) = m_(w) ⋅ g ⋅ x y = d * (r/l) x² + y² = r²x² + d² * (r/l)² = r²$x^{2} = {r^{2}*( {1 - ( \frac{d}{l} )^{2}} )}$$x = {r* \sqrt{}( {1 - ( \frac{d}{l} )^{2}} ) }$

Substituting for x above, we have:

$M_{m_{w}} = {{m_{w} \cdot g \cdot r}*{. \sqrt{}( {1 - ( \frac{d}{l} )^{2}} ) }}$

The moment due to m_(s) is given by:

M _(ms) =m _(s) *g*d

The horizontal force F at S is given by:

F=M/h

Where

h² + d² = l²$h = {l* \sqrt{}( {1 - ( \frac{d}{l} )^{2}} ) }$

Substituting for h above, we have:

$F = {M/( {l* \sqrt{}( {1 - ( \frac{d}{l} )^{2}} ) } }$

Substituting for M, we have

$F = {( {M_{mw} + M_{ms}} )/( {{l* \sqrt{}( {1 - ( \frac{d}{l} )^{2}} ) F} = {( {( {m_{w}*g*r*{.\sqrt{1 - ( \frac{d}{l} )^{2}}}} ) + ( {m_{s}*g*d} )} )/( {l* \sqrt{}( {1 - ( \frac{d}{l} )^{2}} ) } }} }$

Assuming that d<<l, we have

$F \approx {{m_{w}*g*( \frac{r}{l} )} + {m_{s}*g*( \frac{d}{l} )}}$

So, in the final analysis of some of the aforementioned embodiments, theforce due to m_(w) is approximately independent of d. In addition, theforce due to m_(s) is proportional to d.

To improve the performance of pendulum screen shakers, it may bedesirable to have a force that is independent of the displacement d. Asthe force due to the mass on the end of the pendulum is proportional tothe displacement, it may be desirable to minimize this effect. In oneembodiment, it may be noted that a mass on an arm attached to the screenshaker at the pivot, perpendicular to the pendulum, tends to cause aforce that is approximately independent of displacement.

As it is noticed that even a very small force against the screen maycause a visually undesirable dimple, it may be desirable to minimizethis effect. As the voicecoil assembly and the pendulum have some mass,there tends to be some force proportional to the displacement. Thus, inone embodiment that may tend to solve this, it may be possible to extendthe pendulum above the pivot and add a counterweight so that the centerof mass of the pendulum (e.g., not including the arm and mass M_(w)) isat the pivot.

FIG. 9B depicts one such embodiment of a pendulum screen shaker 902comprising such a counterweight. As seen, shaker 902 comprises voicecoil104 (e.g. without any added weight) and positioned below the pivot (e.g.distal from the pivot). An adjustment weight 906 is attached at the endof arm 904 at or near the pivot of the pendulum. Counterweight 908 isshown as attached above (e.g., proximal from) the pivot of the pendulum.Shaker may be given mechanical and electrical attachment at 910. It willbe appreciated that many different designs are possible of a pendulumscreen shaker with counterweight and that the scope of the presentapplication encompasses all such embodiments. In another embodiment, acounterweight may be added to the shaker on the distal side of the mountand the actuator is affixed on the proximal side of the mount. Otherdesign variations are possible and are encompassed by the scope of thepresent application.

FIGS. 10A through 10B and FIGS. 11A through 11C depict several differentviews of one particular embodiment of a pendulum screen shakercomprising a counterweight. FIGS. 12A and 12B depict one embodiment of apendulum screen shaker comprising a counterweight at rest and withrelative motion between positions 1202, 1204 and 1206.

Other Embodiments

FIG. 13 is yet another embodiment of a dual linkage screen shakercomprising a fixed support member 1302 attached at the structure atpivots 1308—which are also in mechanical communication with members 1306a and 1306 b. Members 1306 a and 1306 b are in mechanical communicationswith swinging horizontal member 1310 (at other pivots 1308, as shown).As may be seen, an actuator may be coupled at the end of the swinginghorizontal member, which in turn may bring the actuator into mechanicalcommunication with the screen.

This dual-linkage mount and/or structure (as depicted in FIG. 13) maytend to prevent rotation of actuator 102 as the screen moves. Although,in some embodiments, a long pendulum (i.e., l>>d) may reduce thisrotation, this dual-linkage mount/structure may tend to allow norotation and would tend to eliminate any asymmetrical imprint of theactuator in the screen.

As mentioned above, the placement structure may comprise, for example, adual arm dual-pivot swing that maintains a coupler of the shaking deviceparallel to the screen. In one embodiment, the placement devicecomprises a dual arm dual-pivot swing that maintains a coupler of theshaking device parallel to the screen while moving due to screenmovement. The placement device may comprise, for example, parallelismmechanism configured to maintain a coupler of the shaker parallel to thescreen while moving due to screen movement. The placement device maycomprise a coupler motion parallel placement mechanism configured tomaintain a coupler of the shaker parallel where it would otherwise notbe parallel due to shaker induced movement.

FIG. 14 is one embodiment of voice coil mount in the manner of a divingboard and/or cantilevered section. Member 1402 may have attached/affixed(or in some manner mechanically mated) a diving board (or cantileveredmember) 1410 at 1406. This attachment as shown is bolted—but, it shouldbe appreciated that the mechanical mating may be accomplished by anyknown manner. An optional second member 1408 may be provided for addedstability (and a window and/or void section 1404 may be cut out frommember 1402 to allow for movement). Voicecoil 1412 may be attached tothe diving board section 1410—and by which the actuator (not shown) maybe attached at portion 1414.

As shown, voicecoil 1412 may be mounted with a parallel linkage toprevent rotation of the actuator/voicecoil over the range of traveland/or vibration. In one embodiment, the placement structure maycomprise, for example, a parallelogram shaped device maintains aposition of the shaker parallel to the screen during motion of thescreen due to air currents or other disturbances and a parallelogramthat maintains a face of the shaker parallel to the screen despitemotion of the face due to shaker vibrations. The parallelogram shapeddevice may be mounted, for example on an arm having a cut-away(“window”) that allows the parallelogram shaped device to vibratefreely. Alternatively a device the functions as a parallelogram,maintaining the shaker or its transducer/coupler element parallel to thescreen and mounted such that it can vibrate freely.

In yet another embodiment, a more cost-effective solution may be toconstruct the “diving board” as a single cantilever mount (e.g., wherethe optional second member 1408 is not provided). In this case, therotation of the actuator/voicecoil may be reduced by extending thelength of the cantilever section.

A detailed description of one or more embodiments of the invention, readalong with accompanying figures, that illustrate the principles of theinvention has now been given. It is to be appreciated that the inventionis described in connection with such embodiments, but the invention isnot limited to any embodiment. The scope of the invention is limitedonly by the claims and the invention encompasses numerous alternatives,modifications and equivalents. Numerous specific details have been setforth in this description in order to provide a thorough understandingof the invention. These details are provided for the purpose of exampleand the invention may be practiced according to the claims without someor all of these specific details. For the purpose of clarity, technicalmaterial that is known in the technical fields related to the inventionhas not been described in detail so that the invention is notunnecessarily obscured.

1. A speckle dampening system for dampening speckle on a projectionscreen for a projection display system, said projection display systemcomprising coherent light sources, said system comprising: a set ofactuators, each said actuator capable of emitting a vibration of a setof desired frequencies; a set of rotatably coupled mounts, each of saidset of rotatably coupled mount capable of mounting at least one saidactuator; and wherein said at least one actuator mounted on saidrotatably coupled mount is in moveable mechanical communication withsaid projection screen.
 2. The system of claim 1 wherein said projectionsystem further comprises one of a group, said group comprising: lasers,LEDs, coherent light sources and partially coherent light sources. 3.The system of claim 1 wherein said actuators comprise one of a group,said group comprising: mechanical actuators, voice coils, ultrasoundactuators, electromagnet and solenoid.
 4. The system of claim 1 whereinsaid rotatably coupled mount further comprises: a first support portion,said first support portion capable of mounting an actuator; a secondsupport portion, said second support portion capable of maintaining asubstantially stable frame for said first support portion; and a pivot,said pivot mechanically mating said first support portion to said secondsupport portion.
 5. The system of claim 4 wherein said first supportportion comprise a first length that is substantially longer than therange of motion of the screen.
 6. The system of claim 5 wherein saidfirst length substantially reduces the angular variation of saidactuator with respect to the plane of said projector screen.
 7. Thesystem of claim 5 wherein said first length substantially allowssignificant Z-axis movement without significant change of angle of thefirst support portion with respect to the plane of said projectorscreen.
 8. The system of claim 5 wherein said first length substantiallycomprises a natural frequency that is substantially different from thefrequency of the vibration of said actuator.
 9. The system of claim 4wherein said second support portion comprises a substantially fixedframe.
 10. The system of claim 4 wherein said second support portioncomprises a substantially adjustable frame.
 11. The system of claim 4wherein said system further comprises an additional mass, saidadditional mass placed on said system capable of adjusting the force ofsaid actuator upon said projection screen.
 12. The system of claim 1wherein said system further comprises a magnetic coupling system, saidmagnetic coupling system capable of maintaining a desired mechanicallycommunication of said actuator with said projection screen.
 13. Thesystem of claim 12 wherein said magnetic coupling system furthercomprises: a first magnetic element, said first magnetic element affixedto said projector screen; a second magnetic element, said secondmagnetic element affixed to substantially proximal to said actuator; andsaid second magnetic element being substantially proximal to said firstmagnetic element such that the magnetic force between said first andsaid second magnetic elements capable of substantially maintaining adesired mechanical communication of said actuator with said projectionscreen.
 14. The system of claim 13 wherein said magnetic coupling systemfurther comprises: a controller; at least one of said first magneticelement and said second magnetic element comprises a variableelectromagnet; and said variable electromagnet capable of varying itsmagnetic field under control of said controller.
 15. The system of claim14 wherein said magnetic coupling system further comprises: a sensor,said sensor capable of detecting a characteristic of the mechanicalcommunication of said actuator with said projection screen; and whereinsaid sensor capable of sending sensed data of said characteristic tosaid controller and further wherein said controller sends controlsignals to said electromagnet in response to said sensed data.
 16. Aspeckle dampening system for dampening speckle on a projection screenfor a projection display system, said projection display systemcomprising coherent light sources, said system comprising: a set ofactuators, each said actuator capable of emitting a vibration of a setof desired frequencies; a set of linearly coupled mounts, each of saidset of linearly coupled mount capable of mounting at least one saidactuator; and wherein said at least one actuator mounted on saidlinearly coupled mount is in moveable mechanical communication with saidprojection screen.
 17. The system of claim 16 wherein said projectionsystem further comprises one of a group, said group comprising: lasers,LEDs, coherent light sources and partially coherent light sources. 18.The system of claim 16 wherein said actuators comprise one of a group,said group comprising: mechanical actuators, voice coils, ultrasoundactuators, electromagnet and solenoid.
 19. The system of claim 16wherein said linearly coupled mount further comprises a housing; saidhousing capable of mounting said actuator; a set of bearing, said set ofbearing movably supporting said housing; and a bias, said bias appliedto aid housing and capable of maintaining a desired mechanicalcommunication of the actuator to said projector screen.
 20. The systemof claim 19 wherein said bias further comprises a mass and a pulleywherein said mass communicates a force to said housing to maintain adesired mechanical communication of the actuator to said projectorscreen.
 21. The system of claim 16 wherein said system further comprisesa magnetic coupling system, said magnetic coupling system capable ofmaintaining a desired mechanically communication of said actuator withsaid projection screen.
 22. The system of claim 21 wherein said magneticcoupling system further comprises: a first magnetic element, said firstmagnetic element affixed to said projector screen; a second magneticelement, said second magnetic element affixed to substantially proximalto said actuator; and said second magnetic element being substantiallyproximal to said first magnetic element such that the magnetic forcebetween said first and said second magnetic elements capable ofsubstantially maintaining a desired mechanical communication of saidactuator with said projection screen.
 23. The system of claim 22 whereinsaid magnetic coupling system further comprises: a controller; at leastone of said first magnetic element and said second magnetic elementcomprises a variable electromagnet; and said variable electromagnetcapable of varying its magnetic field under control of said controller.24. The system of claim 23 wherein said magnetic coupling system furthercomprises: a sensor, said sensor capable of detecting a characteristicof the mechanical communication of said actuator with said projectionscreen; and wherein said sensor capable of sending sensed data of saidcharacteristic to said controller and further wherein said controllersends control signals to said electromagnet in response to said senseddata.
 25. The system of claim 19 wherein said bias further comprises: aspring, said spring attached to said actuator; and further wherein theforce from said spring substantially maintains a desired mechanicalcommunication between said actuator and said projector screen.